From owner-freebsd-hackers Mon Sep 15 13:02:53 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id NAA20763 for hackers-outgoing; Mon, 15 Sep 1997 13:02:53 -0700 (PDT) Received: from dyson.iquest.net (dyson.iquest.net [198.70.144.127]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id NAA20735 for ; Mon, 15 Sep 1997 13:02:44 -0700 (PDT) Received: (from root@localhost) by dyson.iquest.net (8.8.6/8.8.5) id PAA02217; Mon, 15 Sep 1997 15:02:27 -0500 (EST) From: "John S. Dyson" Message-Id: <199709152002.PAA02217@dyson.iquest.net> Subject: Re: LRU implementation In-Reply-To: <19970915125503.19344.qmail@hotmail.com> from Douglas Jardine at "Sep 15, 97 05:55:03 am" To: djardine@hotmail.com (Douglas Jardine) Date: Mon, 15 Sep 1997 15:02:27 -0500 (EST) Cc: hackers@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL31 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk Douglas Jardine said: > Hi, > > I had a question on the implementation of Global-LRU in FreeBSD: > What exact implementation does it employ - CLOCK, 2-handed CLOCK > or K-bit LRU? > None of the above. One way to describe it is "Not used recently very often" :-). There are 2nd chance FIFO queues also. > > The 4.3BSD book says that 4.3BSD uses 2-handed CLOCK but the 4.4BSD > book is silent on this topic. Did FreeBSD diverge from 4.4BSD in > this aspect? Does 4.4BSD use a 2-handed clock too? > FreeBSD is very different from 4.4BSD. As I remember, 4.4BSD is a FIFO with 2nd chance. -- John dyson@freebsd.org jdyson@nc.com